It is well known in the automotive repair industry that repairing damaged bodywork parts also involves ensuring that it is not possible to see the difference between the repaired part and the rest of the vehicle. This is particularly the case of bodywork parts such as the bonnet, the boot, the doors, the bumpers and all those parts of the vehicle where flat and curved surfaces are together.
It is also known that in the woodworking and furniture making industry items of furniture and other furnishings in general comprise a variety of shapes, flat surfaces, sharp edges, concave and convex surfaces. When an item of furniture has some or all of these surface features it is essential that the surface finish is of the same quality in all parts of the item of furniture.
In the shipbuilding industry most of the surfaces present have concave or convex shapes. This is necessary not only for technical reasons but also because the shape of these surfaces fulfils an important aesthetic function.
In the construction industry new developments in design have brought with them the need to machine concave and convex surfaces. This is necessary not only for technical reasons but also because the shape of these surfaces often fulfils an important aesthetic function.
In general, many applications require sanding products that provide the same degree of finish on flat and shaped surfaces, maintain high removal rates, provide a high quality surface finish and have a low tendency to clog. In short, these products should be economical to use and provide a high quality surface finish which remains constant over time.
Usually these applications employ non-woven products or traditional abrasives on paper, fabric or plastic film backings in the form of abrasive discs or sheets.
Frequently, abrasives on paper or plastic film supports are preferred to abrasives applied to non-woven fabric supports because they offer superior abrasive performance and higher removal rates.
However, abrasives on paper or plastic film supports have the disadvantage that they are difficult to shape and have a limited range of shapes. In practice this means that they remove too much material in convex zones and too little material in concave zones. The limitations of traditional abrasives become most apparent when sanding large surfaces. Here a high degree of smoothness and uniformity is required which cannot be provided by traditional abrasives which leave behind their characteristic swirl marks.
It is notable that abrasives on non-woven fabric supports are preferred for machining complex, very curved surfaces. However, material removal rates are lower. An additional disadvantage of abrasives applied to non-woven fabric supports is that they do not maintain their cutting capacity for very long and the surface finish provided varies very rapidly.
The document WO 2011/087653 A1 describes a flexible abrasive product with a plurality of elongated channels extending across the work surface and intersecting with each other. These channels act as hinge points and improve the flexibility of the product in two or more directions. These channels assist in carrying the dust particles away from the sanding operation. There are optional openings designed to carry the dust particles away from the channels.
The document WO 01/04227 A2 describes an abrasive product comprising: a rigid backing or support with a first main surface and a second main surface; a plurality of abrasive ceramic compounds, each of which comprises a plurality of abrasive particles distributed inside a porous ceramic matrix; at least one metallic coating which fixes the ceramic abrasive compounds to at least one of the main surfaces of the backing support.